Embodiments described herein relate generally to switch fabrics and more particularly, to the packaging and cabling infrastructure of switch fabrics such as Clos networks.
Clos networks are multi-stage switch networks that provide non-blocking connections between multiple input ports and multiple output ports. A non-blocking network is a network in which a data path through the network can always be established between an idle input port and an idle output port. A three-stage Clos network, for example, has a middle stage connected between an input stage and an output stage. Each stage includes multiple modules. Each input stage module has multiple input ports (n) and is operatively coupled to each middle stage module. Similarly, each output stage module has n output ports and is connected to each middle stage module.
Multiple connections are used to operatively couple the middle stage modules between the input stage modules and the output stage modules. Some known Clos networks use cables to connect the modules. Such cabling can be complex, unorganized and thus, difficult to properly connect and maintain. Other known Clos networks use a midplane disposed between line cards associated with the input stage and the output stage, and line cards associated with the middle stage. In such Clos networks, every position on the midplane to which a line card associated with the middle stage can be coupled includes a line card associated with the middle stage. Accordingly, in switch fabrics that do not use the full capacity of the switch fabric, many middle stage line cards remain underutilized. Such underutilized line cards can take up space, can increase power usage and can be costly.
Thus, a need exists for a switch fabric that is easily connected and maintained. Additionally, a need exists for a switch fabric that can properly and easily be scaled to include the number of switch fabric modules actually used.